Several previous attempts have been made to provide a multiple enclosure cage for keeping a plurality of small animals, typically such popular animals as birds, dogs and cats. Veterinarians, pet stores and breeders of these animals had a particular need to contain a large number of animals in a small area.
Other attempts have been made to provide true isolation of animals in multiple enclosures, to deliver bacteria-free and humidity-controlled air to each cage enclosure, and prevent the transfer of disease from one animal to another. Typically, prior attempts have used some form of recirculation of the air through the cages and have used some form of filtering and air purification technique in the path of the air flow. See, for example, U.S. Pat. No. 3,557,756 issued to Thomas J. Ramsey on Jan. 26, 1971 and entitled "Containerized Storing and Shipping Unit for Animals, Birds and Specimens for Biological Study" and also U.S. Pat. No. 3,924,571 to Frank Brouwer Holman on Dec. 9, 1975 and entitled "Animal Caging System".
While previous techniques reduced the bacteria present in the air system, they were not effective in preventing the transfer of virile respiratory infections, e.g., pneumonitis in cats, from one animal to another. Also, provisions for removal of waste from the individual enclosures often contributed to the cross-contamination of the animals.
It is also desirable, particularly when the animals are to be confined for a long period of time, to minimize the trapped or insecure feelings animals have when they are contained in a small place for a prolonged period.